Organosilicon compositions have superior moisture resistance compared to epoxies, such as epoxy compositions that have been used as adhesives in electronic applications in, for example, the semiconductor packaging industry. However, prior efforts to increase toughness by formulating organosilicon compositions such as described in Leibfried U.S. Pat. No. 5,451,637 and Barnum U.S. Pat. No. 5,242,979 thermoset with very high crosslink density when fully cured and, as a result, are quite brittle and not suitable as adhesives for the IC packages to which they are intended because they tend to crack when subjected to mechanical stress such as thermal cycling/thermal shock.
Moisture-resistant organosilicon compositions, especially compositions with varying modulus of elasticity, are disclosed in co-pending application Ser. No. 08/629,826, filed Apr. 10, 1996 now abandoned and application Ser. No. 08/798,864, filed Feb. 11, 1997. now U.S. Pat. No. 5,859,105 It has now been discovered that such compositions may be improved further to increase their usefulness as an adhesive for electronic applications. The disclosure of the aforementioned applications are expressly incorporated herein by reference.
The present invention provides a novel organosilicon-containing composition suitable for use as an adhesive and capable of rapid curing at low temperature.